Assessment of CA19-9 in Patients' With Thyroid Malignancies

Thyroid cancer is a rare disease that represents approximately 3.8% of all new cancer cases.Incidence of thyroid cancer in north Africa about 2.8% of all new cancer cases with mortality rate about 0.73%.Thyroid malignancies are classified into different groups as follows:Papillary thyroid cancer which is the most common form of thyroid cancer form about 80-90% of all thyroid cancers,Follicular thyroid cancer that forms about 10-15% of all thyroid cancers,Anaplastic thyroid cancer that forms less than 2% of all thyroid cancers,Medullary thyroid cancer that forms about 5-10% and other rare types include thyroid lymphoma, and thyroid sarcoma.

Medullary thyroid carcinoma (MTC) is a rare disease, and its classic tumor marker is calcitonin. However, recently, very aggressive cases have been reported to also secrete carbohydrate antigen 19-9 (CA19-9), and its role as a marker of worse prognosis has been questioned.

CA19-9 was originally described as a gastrointestinal system and pancreas specific tumor marker. Immunohistochemical studies have demonstrated that CA19-9 is expressed in both differentiated and anaplastic thyroid carcinomas. Increased serum levels of CA 19-9 were reported in few patients with anaplastic thyroid cancer.The idea that CA19.9 could be predictive of mortality in MTC stems from early research which showed that serum creatinine and increased carcinoembryonic antigen levels were not important markers in MTC, but that Ca19.9, which is secreted in MTC, was significantly associated with progressive disease.